The interstitial emission mechanism in a vanadium -based alloy

Under nuclear fusion environments, displacement cascades in the potential first protective wall material vanadium (V) and its alloys lead to a large number of point defects. As sink of point defects, grain boundaries are observed to significantly affect the radiation resistance of structured metals. By using potential energy surface searching tools, the interaction between the interstitial-loaded Nu 3 < 110 >{111} symmetric tilt grain boundary (STGB) and the point defects in V-based alloy is investigated. For the self-interstitial atoms (SIA)-loaded STGB, the vacancy located within certain distances from the STGB can be effectively annihilated within several nanoseconds via the interstitial emission (IE) mechanism. If an alloy doping interstitial as a Cr atom substitute the SIA, or the vacancy is stabilized by alloy solutes as Ti atoms forming a solute-vacancy complex near the STGB, IE works more effectively with lower activation energy barriers and less thermal activation time. The results indicate that the STGB-induced IE mechanism raises the radiation resistance of the V-based alloy. The results contribute to the micro-structure and constituent optimizations in designing an excellent V-based first protective wall material. (c) 2020 Elsevier B.V. All rights reserved.